Concern over compulsive internet use is growing in South Korea, where 90 per cent of homes have high-speed broadband connections and some online gameplayers have died from exhaustion after playing for days on end.

The Korean government has set up 140 internet addiction counselling centres, treatment programs in nearly 100 hospitals, and now the rescue camp. Psychiatrists estimate that up to 30 per cent of South Koreans under 18 are at risk of internet addiction.

They spend at least two hours a day online, usually playing games or chatting, though some being treated at the camp say they were on the internet for as much as 17 hours a day. A minority suffer withdrawal symptoms, including anger, when prevented from going on the internet.

Although South Korea makes great play of being the most "connected" country in the world, the problem is increasing in other countries, including the US.

Dr Jerald Block, a psychiatrists at Oregon Health and Science University, estimates that up to 9 million Americans may be at risk of "pathological computer use".

He told the New York Times: "Korea is on the leading edge. They are ahead in defining and researching the problem, and recognise as a society that they have a major issue."

The rescue camp, in woodland near the capital, Seoul, treats the most severe cases, all of whom are male.

During the 12-day sessions, participants cannot use a computer and are allowed only one hour of mobile phone use a day to prevent them playing games via their handsets.

The camp now monitors them constantly after some were sneaking off to log on even during ten-minute breaks before lunch.

Lee Yun-hee, a counsellor, said that the priority was to provide them with a lifestyle rooted in the real world rather than the Internet.

She said: "Young Koreans don’t know what this is like."

One participant on the course, Lee Chang-hoon, 15, told the New Y ork Times that he began using the computer to pass the time while his parents were working and he was home alone.

He would regularly spend up to 17 hours a day in front of the screen, surfing Japanese comics and playing a role-playing game called Sudden Attack.

He played all night, and skipped school two or three times a week to catch up on sleep.

Desperate, his mother, Kim Soon-yeol, sent him to the camp.

"I don’t have a problem," Chang-hoon said in an interview three days after starting the camp. "Seventeen hours a day online is fine."

But after days on the physically gruelling course, Chang-hoon appeared to be changing his tune.

"I’m not thinking about games now, so maybe this will help," he replied. "From now on, maybe I’ll just spend five hours a day online."